The present invention relates to an electro-optical device such as a liquid crystal device and an electronic apparatus comprising the same, such as a liquid projector.
Such electro-optical devices comprise, on an element substrate, a plurality of pixels and a driving circuit for driving the plurality of pixels, while active matrix driving electro-optical devices further comprise pixel switching elements serving as active elements for every pixel. In an electro-optical device such as a liquid crystal display formed by using a liquid crystal device, the structure of the plurality of pixels or the driving circuit usually varies depending on their sizes or performances thereof. Specifically, each pixel switching element in each of the plurality of pixels is made of amorphous silicon or low-temperature polysilicon according to the size or the performance of the liquid crystal display. Furthermore, the driving circuit is mounted on the element substrate as an IC (Integrated Circuit) or an LSI (Large Scale Integration), or the driving circuit is formed in such a way that circuit elements are formed on the element substrate by using the low-temperature polysilicon technique or technology. That is, various types of liquid crystal displays can be manufactured by selecting an appropriate technology from the IC, the LSI, the low-temperature polysilicon technology, and the amorphous silicon technology in view of their the technical properties.
Here, in the driving circuit for a liquid crystal device, if the circuit elements are made of the amorphous silicon, there is a possibility that the driving circuit will not properly operate due to the low current driving efficiency of the circuit. Therefore, the circuit elements may be formed by using the low-temperature polysilicon having higher current driving efficiency than the amorphous silicon, or alternatively the driving circuit may be formed with a plurality of pixels on the element substrate.
In addition, in Patent Document 1, a technology for providing a driving circuit which comprises, as circuit elements, transistors formed on a substrate different from the element substrate by using the low-temperature polysilicon is disclosed. Further, in Patent Document 2, another technology in which a substrate having formed with a driving circuit which has circuit elements formed by using the low-temperature polysilicon is mounted on another substrate, to reduce noise during the driving operation is disclosed.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 8-250745
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2000-214477